HLT
and SMP

HLT (halt) instructions are used by good operating systems to keep processors cool — the halt instruction is sent whenever the processor has nothing to do. However, HLT’s impact can be unpredictable on multi-processor systems, so Be does not enable the feature by default. If you have a dual-CPU setup and want to give it a shot, open ~/config/settings/kernel/drivers/kernel and add the line